The present invention relates to a gasket reinforced by a grommet in combination with a graphite sheet and, particularly, to that of the type adapted for use on the cylinder head of an internal combustion engine.
Recently, for various reasons, for example, for compactness of design, multicylinder internal combustion engines have been manufactured with a very small distance between the cylinders. Accordingly, it is necessary that a grommet used in the cylinder bores of a cylinder head gasket having single or linked 8-shaped holes matching the peripheries of the cylinder bores be formed in one body. This structure of grommet has several disadvantages. For example, due to the pressing of the grommet face during assembly of the grommet in the gasket, and, also, deterioration of the gasket caused by the heat of combustion when in use, there is distortion and non-uniform surface pressure on the gasket body or the portion thereof reinforced by the grommet thereby causing leakage of gas between the adjoining or adjacent cylinder bores resulting in loss of sealing function as a gasket.
Accordingly, an object of the present invention is to provide a gasket reinforced by a grommet in combination with a graphite sheet, which is free from the disadvantages described hereinabove and is capable of functioning efficiently as a gasket even when the area between the adjoining or adjacent cylinder bores is narrow.
Another object of the present invention is to provide a gasket reinforced by a grommet in combination with a graphite sheet of a type particularly suitable for use on the cylinder head of a multicylinder internal combustion engine.